Infants with inborn errors of bile acid metabolism and peroxisomal disorders, including Zellweger's syndrome and infantile adrenoleukodystrophy, commonly have liver disease because of impaired peroxisomal metabolism and accumulation of bile acid intermediates. Using techniques of mass spectroscopy, electron microscopy and MRI- spectroscopy, this study is evaluating the role of bile acid therapy (cholic acid) as therapy for the liver disease with inborn errors of bile acid metabolism/peroxisomal disorders of infancy. During this study period, 3 patients with peroxisomal disease and 1 with previously identified inborn errors of bile acid metabolism, 3-beta hydroxysteroid dehydrogenase/isomerase were evaluated. Subjects are still being recruited for these studies.